Not quite 36 inches
Your review: I bought these to change an existing shelf unit from 48" wide to 36". My old 48" wide beams were exactly 48". I assumed these would be 36" so I had all my shelving cut waiting for the beams to arrive. They are only 35.5" wide. I had to trim all my boards. I should have known better. These are Chinese made compared to my others which were US made. I guess they rounded up. The plus side is that they did at least fit my uprights and worked well.